<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<form action="select_class">
<input type="text" >
    <button>查询大类</button>
</form>
<form action="select_little_class">
    <input type="text" >
    <button>通过大类id查询小类</button>
</form>
</body>
</html>